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Lactose malabsorption and intolerance: a review
Abstract
Food lactose and lactose intolerance is today a hot topic in food and nutrition knowledge. About 70% of the adult world population is lactose-intolerant, due to low levels of intestinal lactase, also called lactase-phlorizin hydrolase (LPH), a β-D-galactosidase found in the apical surface of the intestinal microvilli. This may be due to the loss of intestinal lactase in adulthood, a condition transmitted by an autosomal recessive gene, which differs in humans according to race. According to the cultural-historical hypothesis, the mutation that allows the metabolization of lactose appeared about 10,000 years ago in the inhabitants of northern Europe where mammalian milk continued in the diet after weaning, and lactase-persistent populations were genetically selected in some areas. Many intolerant individuals can tolerate low levels of lactose in their daily diet. Probiotics have also been proposed as an alternative that could avoid some symptoms of lactose intolerance. Many products are marketed nowadays as alternatives to dairy products for lactose-intolerant individuals. However, rules for low-lactose foods are currently not harmonised in the European Union. As scientific knowledge on lactose intolerance has notably advanced in recent decades, the aim of this work was to review the current state of the knowledge on lactose and lactose intolerance, its diagnosis and clinical management, and the various food products that are offered specifically for non-tolerant individuals.
... which is secreted by the villi of the epithelial cells in the small intestine. As a result, the monosaccharides β-D-glucose and β-D-galactose are obtained (7,10). The absorption of these monosaccharides from the organism is carried through passive diffusion or active transport. ...
... As well as glucose, galactose is also absorbed in the intestine to reach the blood vessels. Galactose is a monosaccharide consisting of 6 carbon atoms and it is an epimer of glucose, thus its transporter proteins are also SGLT1 and GLUT 2 (10,12). ...
... Glucose is a direct energy source, and galactose may be used as a component of complex proteins or lipids (glycoproteins and glycolipids). There is also a mechanism where galactose is transformed into glucose via galactokinase and galactose-1-phosphate-uridyl transferase (10). The energy source during activity is the muscle glycogen and blood glucose. ...
The majority (about 70%) of the world's population suffers from lactose intolerance. Lactose intolerance leads to long-term discomfort when consuming milk and dairy products, and hence, to their avoidance. Consequently, the intake of important nutrients is reduced, which potentially has a negative impact on the overall health. Knowing the condition - lactose intolerance - will prevent people from unnecessarily restricting dairy products in their diets. In this study, lactose synthesis and catabolism in the human body are presented, also the types of lactose intolerance, as well as the methods of diagnosing this condition, are discussed. Special attention is paid to the genetic causes of this discomfort and to the tests that can be performed. Solutions for the treatment of lactose intolerance have also been proposed, both up-to-date and easily applicable, as well as future developments.
... In the presence of a congenital or acquired ("secondary") lactase deficiency, lactose cannot be digested and it accumulates in the gut, where-being osmotically active-it leads to an increase in the influx of liquids; this effect, associated with its fermentation by the local microbial flora, gives rise to the typical symptoms of lactose intolerance. If lactose intolerance is suspected, this condition can be easily diagnosed by the Lactose Hydrogen Breath Test (LHBT) [3]. This test measures the concentration of hydrogen (H 2 ) in the air exhaled by the patient after the oral consumption of lactose, produced by the intestinal fermentation of the sugar [4,5]. ...
... Among these, a concomitant condition of IBS, probably secondary to visceral hypersensitivity, might characterize this specific disease. Consequently, SRMI is very common in patients with IBS, and lactose intolerance is often diagnosed in these patients regardless of the LHBT results [3,5,14,15]. ...
... The subgroup of lactose tolerants, who had the highest frequency and absolute values of FCP positivity, might be characterized by a higher inflammatory status due to a higher prevalence of patients with CMPA, whereas digesters/intolerants could be suffering especially from IBS. In this latter group, in fact, symptoms could be caused by a simple "nocebo effect" or by trigger effect on visceral hypersensitivity when patients consume milk and/or dairy products, or by the concomitant consumption of other foods rich in other Fermentable, Oligo-, Di-, Monosaccharides and Polyols (FODMAPs), known for their ability to trigger symptoms in patients with IBS [3,14]. By contrast, the maldigesters/intolerants might have a "true" lactose intolerance, but in a percentage of cases, this could probably be associated with a slight intestinal mucosa inflammation. ...
Citation: Seidita, A.; Mansueto, P.; Giuliano, A.; Chiavetta, M.; Soresi, M.; Carroccio, A.; the Internal Medicine Study Group. Fecal Calprotectin in Self-Reported Milk Intolerance: Not Only Lactose Intolerance. Nutrients 2023, 15, 1048. Abstract: The hypothesis is that inflammatory/allergic conditions should be considered in self-reported milk intolerance (SRMI) patients who test negative and/or are asymptomatic at Lactose Hydrogen Breath Test (LHBT). We analyzed fecal calprotectin (FCP) values in SRMI patients to investigate the frequency of a "positive" intestinal inflammation marker and its correlation with lactose tolerance/intolerance. Data from 329 SRMI patients were retrospectively analyzed; according to the positive/negative results (maldigester/digester) and the presence/absence of symptoms reported during LHBT (intolerant/tolerant), patients were divided into: 'lactose tolerants' (n. 104), 'maldigesters/intolerants' (n. 187), 'digesters/intolerants' (n. 38). FCP values were analyzed in all three subgroups. A percentage of SRMI patients complained of constipation (>15%), extraintestinal symptoms (>30% including anemia), multiple food hypersensitivity (7.6%) and had intraepithelial lymphocytic infiltration at duodenal biopsy (>50%). Over 50.0% showed FCP values above the normal limit. Lactose tolerants and maldigesters/intolerants had higher positivity frequencies (p < 0.0001, for both) and absolute values (p = 0.04, for maldigesters/intolerants) of FCP compared to digesters/intolerants. FCP was not useful to differentiate tolerant from intolerant subjects (AUC 0.58). Our data suggest the existence of an allergic/inflammatory pathogenetic mechanism in a subset of SRMI subjects. FCP results are in keeping with this hypothesis, even if they cannot differentiate lactose tolerant from intolerant patients.
... It is estimated that lactose represents approximately 6% of the carbohydrates consumed in Western countries [1]. Although dairy product consumption is much higher in developed countries than in developing countries, the share in developing countries is continuously increasing [1,2]. ...
... It is estimated that lactose represents approximately 6% of the carbohydrates consumed in Western countries [1]. Although dairy product consumption is much higher in developed countries than in developing countries, the share in developing countries is continuously increasing [1,2]. ...
Purpose
Bacillus coagulans GBI-30, 6086 (BC30) was previously shown to improve nutrient digestibility and amino acid absorption from milk protein in vitro. However, the effect of supplementation with this probiotic on lactose digestibility has not yet been evaluated in vivo.
Methods
Wistar female rats were exposed to an acute high-lactose diet (LD; 35% lactose) meal challenge after 7 days of administration of BC30 (LD-BC; n = 10) or vehicle (LD-C; n = 10). Rats treated with vehicle and exposed to control diet (CD; 35% corn starch) meal were used as controls (CD-C; n = 10). Carbohydrate oxidation (CH_OX) and lipid oxidation (L_OX) were monitored by indirect calorimetry before and after lactose challenge. After the challenge, rats were treated daily with vehicle or probiotic for an additional week and were fed with CD or LD ad libitum to determine the effects of BC30 administration in a lactose-induced diarrhoea and malnutrition model.
Results
LD-C rats showed lower CH_OX levels than CD rats, while LD-BC rats showed similar CH_OX levels compared to CD rats during the lactose challenge, suggesting a better digestion of lactose in the rats supplemented with BC30. BC30 completely reversed the increase in the small intestine length of LD-C animals. LD-BC rats displayed increased intestinal mRNA Muc2 expression. No significant changes were observed due to BC30 administration in other parameters, such as serum calprotectin, intestinal MPO activity, intestinal A1AT and SGLT1 levels or intestinal mRNA levels of Claudin2 and Occludin.
Conclusion
Treatment with BC30 improved the digestibility of lactose in an acute lactose challenge and ameliorated some of the parameters associated with lactose-induced malnutrition.
... The search attributes are visible to the consumers prior to purchase; hence, they can become aware of them before choosing and consuming the product. The experience attributes are visible only after the purchase of the product -duration and taste, for example -and therefore require some kind of A Survey on Consumers with Lactose Intolerance in Italy: Their Perception, Habits and Needs When Shopping for Groceries 31 "proof" by the consumer. Finally, the credence characteristics are never accessible to the consumer, and they are what we actually refer to in relation to LF products. ...
... The attention to taste as the primary driver is confirmed by the preference of 54.3% (n = 208) of subjects to vary and try new LF products. Not renouncing a conventional taste could be due to LI diagnosis usually occurring in adulthood, given that enzyme activity diminishes with increasing age [31]. Therefore, lactose-intolerant people expect to find the same taste in LF products that they were used to before the diagnosis of LI. ...
This study aimed to investigate perceptions, habits and needs of a new growing consumers' category: individuals with lactose intolerance (LI). This digestive disorder affects about 70% of the world population who need to follow a lactose-free (LF) diet to respite symptoms, so that the purchase of suitable LF foods becomes essential. An ad hoc questionnaire was administered to 384 subjects with LI and the collected data were imported into a SAS dataset for statistical analyses. Consumers with LI need to do grocery shopping quickly and safely (79.2%), avoiding spending time reading unclear labels. The dominant factors determining food choices resulted in taste (26.6%) and price (21.3%) while relevant is the need to taste new products (55.7%). A growing demand for LF references, especially sweet (24.9%) and savoury (12.6%) bakery goods and ice cream (18.4%) was reported. The first in-depth study about consumers with LI has been carried out. The results can be exploited as new and widespread cultural model of consumption of LF products by food companies to sell the most desired products to this consumer category. An improvement of LF labelling through a recognizable certification trademark, such as Lfree ® , could represent a good strategy for quick and safe purchases. Consumers would be protected and assisted during their grocery shopping making it quicker, also complying with the new safety measures for Covid-19 pandemic. These findings shed light on a poorly-known topic that is increasing its relevance.
... β form shows the solubility of 500 g L -1 , melts at 242°C, and has a resolving power of -35°C (9). The balance of both isomers in milk is affected by any specialized treatment, mainly due to the temperature employed. ...
... This is considered a normal condition, and these human beings can digest lactose and absorb its contents and are referred to as lactase persistent or lactose tolerant individuals. Since the enzyme is secreted from the edge of intestinal villi, it is most likely impaired due to intestinal mucosa lesions (9). Hyperproliferation of intestinal bacteria may also reduce the level of this enzyme since the bacterial elastases are released during the breakdown of the brush border membrane affecting the synthesis of the enzyme (20). ...
Lactose intolerance is a common pathology that occurs due to the reduced activity of β-galactosidase leaving undigested lactose in the intestine. About 70% of the world population suffers from this condition. The gastro intestinal symptoms associated with this condition are diarrhoea, pain, nausea, bloating, flatulence, etc. It has been reported that these individuals are at a risk of developing several other pathologies like irritable bowel disease, osteoporosis, etc. Hence, proper diagnosis and treatment is essential for dealing with this condition. Various methods are used for providing an accurate diagnosis, such as hydrogen breath test (HBT), lactose intolerance test, genetic test, intestinal biopsy, etc. Depending on the type of intolerance, several methods are adopted for treating it, such as replacing enzyme, using exogenous enzymes, following lactose free diet, as well as consuming prebiotics and probiotics. Different methods are applied to synthesize lactose free dairy products to help lactose intolerant individuals suffering from important vitamins and minerals deprivation. Recently, plant-based milks are also used as a substitute for providing calcium and vitamins. The last few years have seen improvement in the quality and availability
of lactose-free dairy products offering tempting foodstuffs to consumers. This narrative article aimed to review the existing science on lactose intolerance, along with its epidemiology, diagnosis, and clinical management.
... Once lactose is produced, it is excreted with milk [11]. The lactose content in milk is inversely proportional to protein and fat, and varies according to the mammal species [3,12,13]. ...
... Intestinal LPH activity increases until week 34 from conception and reaches its peak around the first months after birth. Afterwards, LPH activity gradually decreases because of a lower lactase gene expression, resulting in the lactase non-persistence condition (LNP) [12]. In humans, a small portion of the population maintains LPH activity throughout adulthood; however, this is not common in other mammals. ...
The recent growing interest in lactose intolerance has resulted in the proliferation of lactose-free products by food manufacturing companies. Since updated papers about lactose and its uses are missing, the main purpose of this review is to investigate this sugar comprehensively. Firstly, its chemical and physical characteristics were studied, following its employment in the food and drug industries. The positive and negative health-related effects of lactose are reported, focusing on the condition of lactose intolerance, for which an adequate lactose-free diet has to be followed to avoid symptoms that impairs quality of life. Considering that EU legislation on lactose-free product labelling is still controversial, suitable options for producing and identifying lactose-free products are suggested, in order to meet lactose-intolerant people’s needs.
... The colonic bacteria cause the feces to be acidic. This acidity occurs after lactose consumption, so in case of acidic stool, the individual was diagnosed as lactose intolerant 17 . ...
... The discrepancy in percentages among studies was caused by a lack of standardization in the amount of lactose prescribed for the tests, as well as the conditions under which they were performed and their interpretation, as well as genetic variability in the study populations 17 . ...
Introduction:
Lactose intolerance (LI) is the failure to digest foods and beverages containing the lactose present in milk. LI can present by many digestive symptoms.
Objective:
To validate the modified CoMiSS score for prediction of LI, that was confirmed by a stool acidity test.
Patients and methods:
A cross-sectional study, was conducted at Ain Shams University Hospitals/Gastrointestinal Clinics, and included one hundred adult participants during the period from December 2018 to December 2019. Enrolled patients had one or more gastrointestinal symptoms and were subjected to a stool acidity test (fecal PH test) as a reference test and modified CoMiSS as an index test. Results: The mean age of participants was 35.30 ± 10.714 years old; 55% were females, and their mean body mass index (BMI) was 23.08 ± 2.080 kg/m2, with no significant relation between LI and patients` gender or BMI. Out of the studied participants 24% had positive stool PH, LI diagnosed according to modified CoMISS was present among 19% of them. The mean value of modified CoMISS Score was significantly higher in positive cases (12.37) compared to negative LI participants (2.33) as p < 0.001. Area under ROC Curve was 0.998, at the selected cut-off value 8, the sensitivity was 89.5% and specificity was 100% thus, levels of questionnaire scoring of 8 or higher would indicate presence of lactose intolerance. Conclusion: Modified CoMiSS is a simple, fast, and easy-to-use tool that can predict LI, with a cut-off value of >8, the Area under the ROC Curve was 0.998, sensitivity 89.5%, and specificity was 100%.
... (25) Se estima que en todo el mundo dos tercios de los habitantes adultos sufren este trastorno. (24) Siendo estos prevalentes en la población Asiática donde afecta entre el 90 y el 100% de las personas; la incidencia en la población africana y árabe es del 80%, mientras que se estima que solo afecta alrededor del 15% de la población europea (24), (25,26) .Para esta diversidad se acepta la hipótesis de una mutación que solventa la enzima lactasa a partir de la ganadería y consumo de lácteos dando lugar a individuos con lactasa persistente (24) . ...
Resumen Introducción La prevalencia e incidencia de pacientes en consulta privada, que presentan síntomas dispépticos como queja principal, cada vez aumenta, por lo que proponemos determinar la etiología en cada paciente, determinando, la intolerancia a la lactosa (IL) y el síndrome de sobrecrecimiento bacteriano intestinal (SIBO), como las más altas en prevalencia. La prueba de H2 espirado, es un método práctico y accesible, no invasivo, y está validada en numerosos estudios, como método diagnóstico para la Intolerancia a la Lactosa y el Sobrecrecimiento Bacteriano. Objetivos Establecer la frecuencia de la intolerancia a la lactosa y el sobrecrecimiento bacteriano en pacientes con dispepsia sin signos de alarma en el centro de especialidades Gastroenterología González de la ciudad de Cuenca-Ecuador. Metodología Es un estudio observacional descriptivo, de corte transversal, que recopiló los datos mediante el análisis documental (historias clínicas) y prueba de H2 espirado aplicadas a 310 individuos de ambos sexos con un promedio de edad de 50±17 años, en el periodo febrero del 2019 a febrero del 2020. Resultados Se observó que la intolerancia a la lactosa se presenta en el 29% de los casos, mientras que el sobrecrecimiento bacteriano intestinal en el 20.3%, de los pacientes con síntomas dispépticos. Conclusiones La intolerancia a la lactosa tanto como el síndrome de sobrecrecimiento bacteriano (SIBO), son síndromes frecuentes que se presentan en la consulta privada, por lo que se debe tener en cuenta, en la investigación de un paciente con síntomas dispépticos, y no se debe descartar antes de realizar una prueba diagnóstica como el test de H2 espirado. Revista Médica Vozandes Volumen 34, Número 1, 2023 Palabras clave: Dispepsia, dispepsia funcional, intolerancia a la lactosa, síndrome de sobrecrecimiento bacteriano intestinal, test de H2 espirado.
... documented lactose maldigestion or the intolerant ones may carry the lactase persistence gene [19]. Therefore, the LNP status may not necessarily predict the amount of milk consumption in the population, for example, individuals with the CC genotype may not avoid milk consumption as they may not have intolerant symptoms during the surveyed period as their LCT gene expression may remain well-functioned. ...
Background & aims:
Studies have determined that people with genetically defined lactase non-persistence have lower dairy intake that may lead to an increase risk of various non-communicable diseases. Furthermore, lactase non-persistence itself has been associated with insulin resistance. However, data on lactase non-persistence status and dairy intake in developing countries are sparse. We therefore aimed to define 1) the prevalence of lactase non-persistence among individuals with diabetes and non-diabetes in Thai population and 2) the links between lactase non-persistence, milk consumption, and risk of diabetes mellitus.
Methods:
We conducted a case-control study from participants of the National Health Examination Survey. DNA was isolated from the blood for LCT -13910C>T (rs4988235) polymorphism and processed using the Bio-rad c1000 touch thermal cycler and MALDI-TOF Mass Spectrometry MassARRAY Typer v4.0 (Agena Bioscience, San Diego, CA, USA) at the Center for Medical Genomics, Faculty of Medicine Ramathibodi Hospital. Cases were participants with previously diagnosed diabetes mellitus or fasting plasma glucose ≥126 mg/dL (n = 1,756) vs. the controls (n = 2,380).
Results:
We included 4,136 participants, 62% female, and 98.8% were > 30 years old. Homozygous CC genotype (i.e., lactase non-persistence) was noted in 98.6% and only 1.4% carried heterozygous CT. Most (76%) consumed milk <1 portion/month. Participants with either CC or CT genotype had comparable milk consumption and the risk of diabetes mellitus. Males, older adults, and lower education had a lower chance of consuming milk at least one portion per month. Besides various baseline variables, we found that higher milk consumption was associated with a lower DM risk (P = .01).
Conclusion:
The prevalence of lactase non-persistence in Thai population is very high. A significant difference in milk consumption frequency in relation to the lactase non-persistence status was not found. However, higher milk consumption is associated with a lower risk of diabetes mellitus.
... After breakdown, lactose is converted to two monosaccharides, glucose, and galactose. [12] Sodium-glucose linked transporter-1 (SGLUT-1), a protein which is localized in the enterocyte membrane, helped their absorption by active transport method. It also co-transports galactose or glucose and two sodium ions (Na + ) from the intestinal lumen to the cytoplasm of these cells. ...
Intolerance to lactose-containing foods is not so uncommon. Clinical symptoms of lactose intolerance
in children include abdominal pain, flatulence, and diarrhea after ingesting milk or milk-containing
products. These symptoms have been attributed to lactose malabsorption, which results from low
levels of small intestinal lactase. Reduced lactase level may be due to mucosal injury or, much more
commonly, reduced genetic expression of the enzyme lactase-phlorizin hydrolase. However, lactose
intolerance cannot be cured. Still, it can be adequately managed by using lactose-reduced milk and
milk products and over-the-counter supplements of lactase, lactose-depleted products, and other
essential milk nutrients such as calcium. This article will review the clinical manifestations, diagnosis,
and management of lactose intolerance in children.
... After breakdown, lactose is converted to two monosaccharides, glucose, and galactose. [12] Sodium-glucose linked transporter-1 (SGLUT-1), a protein which is localized in the enterocyte membrane, helped their absorption by active transport method. It also co-transports galactose or glucose and two sodium ions (Na + ) from the intestinal lumen to the cytoplasm of these cells. ...
Intolerance to lactose-containing foods is not so uncommon. Clinical symptoms of lactose intolerance in children include abdominal pain, flatulence, and diarrhea after ingesting milk or milk-containing products. These symptoms have been attributed to lactose malabsorption, which results from low levels of small intestinal lactase. Reduced lactase level may be due to mucosal injury or, much more commonly, reduced genetic expression of the enzyme lactase-phlorizin hydrolase. However, lactose intolerance cannot be cured. Still, it can be adequately managed by using lactose-reduced milk and milk products and over-the-counter supplements of lactase, lactose-depleted products, and other essential milk nutrients such as calcium. This article will review the clinical manifestations, diagnosis, and management of lactose intolerance in children.
... Lactase deficiency in adults may be caused by a recessively inherited polymorphism of the LCT gene. The lactase persistence phenotype is inherited as an autosomal dominant trait [17][18][19]. ...
Intolerance to dairy products resulting from the abnormal digestion of milk sugar (lactose) is a common cause of human gastrointestinal disorders. The aim of this study was to show that the-13910 C>T LCT gene polymorphism, together with genotypes of selected VDR gene polymorphisms and diet and nutritional status parameters, can impact the prevalence of vitamin D and calcium deficiency in young adults. This study was conducted on a group of 63 people, which comprised 21 individuals with primary adult lactase deficiency, and a control group of 42 individuals with no hypolactasia. The LCT and VDR gene genotypes were assessed using PCR restriction fragment length polymorphism (PCR-RFLP) analysis. A validated HPLC method was used to determine serum concentrations of 25(OH)D 2 and 25(OH)D 3. Atomic absorption spectrometry was used to determine calcium levels. Their diets (self-reported 7-day estimated food record), estimated calcium intakes based on the ADOS-Ca questionnaire and basic anthropometric parameters were assessed. The CC genotype associated with hypolactasia was found in 33.3% of the subjects. The presence of the CC variant of the LCT gene polymorphism in the study group of young Polish adults was found to be associated with significantly lower milk (134.7 ± 66.7 g/d vs. 342.5 ± 176 g/d; p = 0.012) and dairy product consumption (78.50 ± 36.2 g/d vs. 216.3 ± 102 g/d; p = 0.008) compared with lactase persistence. At the same time, people with adult-type primary intolerance were found to have statistically significant lower serum levels of vitamin D and calcium (p < 0.05). There was a higher chance of vitamin D and calcium deficiency and a lower intake in the group exhibiting lactase non-persistence (OR > 1). The AA variant of the VDR gene's BsmI polymorphism present in people with hypolactasia may further contribute to an increased risk of vitamin D deficiency. Exclusion of lactose from the diet, combined with impaired vitamin D metabolism, may also lead to inhibited calcium absorption by the body. Further research should be carried out on a larger group of subjects to clarify the relationship between lactase activity and vitamin D and calcium levels in young adults.
... In children, long-term dietary exclusion of milk products is associated with lower height and bone mineral density, and higher fracture risk [33,43]. In our study, dairy intake was not higher in lactose-tolerant children than in children with genetic predisposition PLI. ...
Background:
Primary lactose intolerance (PLI) is characterized by the inability to digest lactose. Homozygotes for the lactase gene polymorphisms (CC or GG) are considered to be genetically predisposed to PLI. Still, symptoms may only be present later in life. The evidence supporting a link between PLI, dairy intake, and quality of life (QoL) is limited in children.
Aim:
This study investigates the link between LCT polymorphisms and suggestive symptoms and the influence of the genetic predisposition to PLI on dairy intake and QoL in Romanian children.
Materials and methods:
We recruited consecutive children evaluated in our ambulatory clinic. We asked all participants to complete a visual-analog symptoms scale, a dairy intake, and a QoL questionnaire. We used strip genotyping to identify genetic predisposition to PLI.
Results:
51.7% of children had a CC genotype, and 34.5% also had a GG genotype. Most children reported no or mild symptoms. Dairy intake and QoL were similar across study groups.
Conclusions:
Our study shows that genetic predisposition does not necessarily assume the presence of specific symptoms. Genetic predisposition to PLI did not lead to dairy avoidance, nor did it negatively influence our children's QoL.
... Indigestion to lactose in adultsis now the most common among population of East Asian region, with 70-100%of those affected in this groups. Lactose indigestion is also very popular in population of western African, Greek, Arab and Italian origin (7). The incidence of lactose indigestion is minimum in communities with longer history of reliance on malted milkproducts as a significant part of food source. ...
... a. Production of lactose-free products for lactose-intolerant people Over 70% of the world's population suffers from lactose intolerance i.e., the inability to digest lactose due to the absence of BG in the small intestine [5]. Ingested lactose reaches the large intestine in its intact form and is fermented by colonic microorganisms, producing short chain fatty acids and gases that cause abdominal pain, diarrhoea, and nausea [6,7]. ...
β-Galactosidase is a glycoside hydrolase enzyme that possesses both hydrolytic and transgalactosylation properties and has several benefits and advantages in the food and dairy industries. The catalytic process of β-galactosidase involves the transfer of a sugar residue from a glycosyl donor to an acceptor via a double-displacement mechanism. Hydrolysis prevails when water acts as an acceptor, resulting in the production of lactose-free products. Transgalactosylation prevails when lactose acts as an acceptor, resulting in the production of prebiotic oligosaccharides. β-Galactosidase is also obtained from many sources including bacteria, yeast, fungi, plants, and animals. However, depending on the origin of the β-galactosidase, the monomer composition and their bonds may differ, thereby influencing their properties and prebiotic efficacy. Thus, the increasing demand for prebiotics in the food industry and the search for new oligosaccharides have compelled researchers to search for novel sources of β-galactosidase with diverse properties. In this review, we discuss the properties, catalytic mechanisms, various sources and lactose hydrolysis properties of β-galactosidase.
... Lactose can be removed from dairy products by hydrolyzing it in the milk by means of the β galactosidase enzyme, which converts lactose into glucose and galactose, or with the prior ultrafiltration of the milk, followed by the action of the lactase enzyme [4,5]. The hydrolysis of lactose can influence both the technological and the sensory properties of products [6]. ...
Semi-hard pressed goat’s cheese, a traditional matured cheese in Andalusia, has a residual lactose content that may affect people with intolerance to that carbohydrate. Nowadays, lactose-free dairy products are characterized by presenting a scant sensory quality, far removed from their traditional profile for their pronounced sweet and bitter taste and aroma related to Maillard reactions. The aim of this work was to make a cheese with a similar sensory profile to that of the traditional Andalusian one but without lactose. For this purpose, the doses of the enzyme lactase that would be necessary to add to the milk were investigated so that, during the manufacturing of the cheese, there would remain enough lactose for the starter cultures to trigger lactic fermentation and, in turn, to spark the cheese’s own maturity processes. The results show that the combined action of lactase (0.125 g/L, 0.250 g/L, 0.5 g/L, and 1 g/L) and of the lactic bacteria reduces the final content of lactose to below 0.01%, complying with the European Authority of Food Safety’s recommendations for considering the cheeses as being under the denomination “lactose-free”. The physicochemical and sensory values resulting from the different batches of cheese obtained indicate that the lowest dose studied (0.125 g/L) had very similar ones to those of the control cheese.
... Natomiast spośród różnych typów występującej nietolerancji laktozy tylko wrodzony niedobór laktazy wymaga całkowitej eliminacji spożywania cukru mlecznego. Choroba ta występuje bardzo rzadko i do tej pory opisano tylko kilkadziesiąt jej przypadków na świecie [13,14]. Znacznie częstsza jest hipolaktazja typu dorosłych, która charakteryzuje się stopniowym spadkiem aktywności laktazy wraz z wiekiem. ...
Introduction and Objective.
Milk contains all the ingredients (protein, fat, sugar, minerals, vitamins) needed for the proper development of young organisms. Therefore, humans have been including milk of domesticated mammals in their diet for over 10,000 years. The question remains whether, due to the growing interest in plant-based drinks, there is still room for dairy products in the diet of an average Pole. The study aimed to characterize fresh milk in terms of its nutritional value and to emphasize its importance in nutrition. To implement the discussed topic, the resources of the PubMed database and Google Scholar, as well as the official websites of dietary and nutritional organizations were analyzed. Brief description of the state of knowledge.
Milk is a natural product that has played an important role in human nutrition for hundreds of generations and its bottling and packaging technology has remained simple and unchanged for many years. In addition to the above-mentioned macro nutrients,it contains many biologically active substances (including immunoglobulins, hormones, growth factors, cytokines, and nucleotides) that affect the proper functioning of the immune system and the transport and absorption of vitamins and minerals. On the other hand, plant-based drinks are processed products with lower nutritional value, therefore they can be consumed occasionally and not as a substitute for conventional milk.
Summary.
It is increasingly more common to replace natural milk and its products with artificially fortified plant drinks,which is detrimental to human health.
... Around 70% of the adult population worldwide is lactose-intolerant, reaching 95-100% in Asians, for example. This makes it necessary for the food industry to apply technologies to reduce the lactose contents in products intended for these lactose-intolerant people in order to avoid symptoms such as diarrhea, flatulence, and abdominal cramps that appear with the consumption of lactose [3,4]. Moreover, hydrolysis with β-galactosidase contributes to the formation of galactooligosaccharides (GOS) [5][6][7], which are beneficial to humans [8] and improve the technological and sensory characteristics of foods [9][10][11]. ...
The enzyme β-galactosidase catalyzes the hydrolysis of lactose into glucose and galactose, although for its effective application it is necessary to establish techniques for purification, concentration, or polishing, such as membrane separation processes, in particular ultrafiltration. The present study aimed to investigate ultrafiltration and diafiltration applied as initial steps for concentration and salt removal, respectively, in the β-galactosidase purification processes. Additionally, the influence levels of the pH (6.5, 7.7, or 7.5), membrane molecular weight cut-off (30, 50, 60, or 100 kDa), operating pressure (1.5, 2.0, or 2.5 kgf/cm²), and ionic strength of the ultrafiltration using NaCL or KCl (0.01–0.1 M) were evaluated considering the enzyme recovery, purification, retention, and concentration factors in relation to the proteins, volume, activity, and protein flux and yield of the processes. The ultrafiltration of the crude enzyme extract at pH 7.5 and 1.5 kgf/cm2 with a 50 kDa polyethersulfone membrane resulted in a volume concentration of the β-galactosidase extract up to 7.1-fold greater, a purification factor 1.2-fold greater, and an enzyme recovery rate of 108.9% by eliminating metabolites during the purification process. In addition, the lowest flux variation range (16.0 to 13.1 L/m²·h) was observed under these same conditions, thereby representing a decrease of 18.0%. An increase in the operating pressure and the addition of salts results in reduced enzyme recovery (up to 38% of the process yield (734.1 to 453.7 U/h) and up to 40% of the enzyme recovery rate (108.9 to 60.6%) during the ultrafiltration using NaCl, respectively). The operation in the diafiltration mode allowed salt removal after the purification of β-galactosidase (enzymatic recovery rates above 93.4%) via precipitation and ion-exchange chromatography elution and as part of an aqueous two-phase system using 6 diafiltration cycles, thereby revealing its application potential.
... In the other hand, lactase persistence (LP), the ability to digest large amounts of lactose during adulthood owing to the maintenance of lactase activity, is prevalent in Europeans, Arabs and pastoralist populations of Africa (Campbell & Ranciaro, 2021;Swallow, 2003). Symptoms of LI usually include abdominal pain, bloating, flatulence acid stools, perianal erythema and diarrhea, and less commonly nausea, vomiting, constipation, anorexia and weight loss, being most of them driven by lactose colonic fermentation byproducts (Lomer et al., 2008;Toca et al., 2022;Ugidos-Rodríguez et al., 2018). Diverse factors remark the complex interrelations between symptomatology, physiology, microbiome and metabolome (Szilagyi, 2015;Usai-Satta et al., 2022). ...
Uruguay has one of the highest per capita milk intakes worldwide, even with a limited supply of lactose-free products; furthermore, the admixed nature of its population is well known, and various frequencies of lactase persistence (LP) are observed in the source populations. We aimed to contribute to the understanding of the relation between allelic variants associated with LP, milk consumption, digestive symptoms, and genetic ancestry in the Uruguayan population. Samples of saliva or peripheral blood were collected from 190 unrelated individuals from two regions of Uruguay, genotypes for polymorphic sites in a fragment within the LCT enhancer were determined and allelic frequencies calculated in all of them. Data were collected on frequency of milk and dairy consumption and self-reported symptoms in a subsample of 153 individuals. Biparental and maternal ancestry was determined by analyzing individual ancestry markers and mitochondrial DNA. Twenty-nine percentage of individuals reported symptoms attributed to the ingestion of fresh milk, with abdominal pain, bloating and flatulence being the most frequent. European LP-associated allele T-13910 showed a frequency of 33%, while other LP-associated alleles like G-13915 and T-14011 were observed in very low frequencies. Associations between self-reported symptoms, fresh milk intake, and C/T-13910 genotype were statistically significant. No evidence of association between genetic ancestry and C/T-13910 was found, although individuals carrying one T-13910 allele appeared to have more European ancestry. In conclusion, the main polymorphism capable of predicting lactose intolerance in Uruguayans is C/T-13910, although more studies are required to unravel the relation between genotype and lactase activity, especially in heterozygotes.
... Unfortunately, there is no significant data showing epidemiological and clinical features of lactose intolerance in the Bulgarian population. When looking at the problem worldwide, about 70% of the world's population has lactose intolerance (Ugidos-Rodríguez et al., 2018). ...
Lactose is an important component of mammalian milk. It is a disaccharide also
called “milk sugar”. In healthy individuals, lactose enters the intestinal lumen and is
being hydrolyzed to glucose and galactose by the enzyme lactase. There are people
with reduced lactase activity and the disaccharide is hydrolyzed by the microorganisms in their gut. This leads to lactose malabsorption which leads to
symptoms such as diarrhea, nausea, gas, and abdominal pain. The condition is called lactose intolerance. Those people with less or no amount of the enzyme lactase are forced to avoid lactose-containing foods or pre-process them in order to hydrolyze the milk sugar before consuming the product. This paper presents a method by which anyone could get lactose-free milk at home. The so-called “enzyme bag” resembles a tea bag that is dunked into a glass of milk. It uses the biodegradable, biocompatible, and non-toxic polysaccharide – chitosan as an inert and harmless carrier, and the immobilized enzyme beta-galactosidase. The process does not require special equipment - is performed at room temperature and is fast, easy, and convenient. The future application of this method allows a few tools and a few easy steps to solve the problem of a large number of people with lactose intolerance.
... In addition to genetic factors, the reduced activity of lactasephlorizin hydrolase (LPH) can result from the over growth of bacteria in the small intestine, damage of the mucosa which occur in coeliac disease, CD, and infection (25,26) . Moreover, the short contact time in the intestine and the inhibition of the sodium-dependent glucose transporter contributes to the incomplete absorption of carbohydrates in the intestine. ...
Background
The role of dairy foods in inflammatory bowel disease (IBD) has been controversial and it is debatable if patients with IBD should avoid milk and dairy products or not, as well as the relationship between these foods and symptoms among those population.
Objective
This multi centric cross-sectional study designed to evaluate if it is really necessary to deprive IBD patients from consumption of dairy foods.
Methods
A multicenter study with 12 gastroenterology referral centers in four countries was designed to evaluate gastrointestinal (GI) symptoms after consumption of dairy foods from all outpatients with IBD during 6 months and to compare patients treated at the same centers without IBD (non IBD cases).
Results
Overall 1888 cases included (872 IBD patients and 1016 non IBD cases). 56.6% of participants were female with average age of 40.1 years. Racially 79.8% participants were Caucasians and originally they were citizens of 10 countries. Relative prevalence of IBD was higher in Africans and Indians and the most frequent prevalence of dairy foods intolerance was seen in Asians. Among IBD patients, 571 cases diagnosed as ulcerative colitis and 189 participants as Crohn’s disease. Average duration of diagnosis as IBD was 6.8 years (from 2 months to 35 years). The most prevalent GI symptoms after consumption of all the dairy foods were bloating and abdominal pain. Totally, intolerance of dairy foods and lactase deficiency was more prevalent among IBD patients in comparison with non IBD cases (65.5% vs 46.1%, P=0.0001). But the rate of GI complains among IBD patients who had not any family history of lactase deficiency, history of food sensitivity or both were 59.91%, 52.87% & 50.33% respectively and similar to non IBD cases (P=0.68, 0.98 & 0.99 respectively).
Conclusion
The rate of dairy foods intolerance among IBD patients without family history of lactase deficiency or history of food sensitivity is similar to non IBD cases and probably there is no reason to deprive them from this important source of dietary calcium, vitamin D and other nutrients.
Keywords:
Inflammatory bowel disease; lactase deficiency; dairy foods; bloating; abdominal pain
... In North Europe, 90% of the population can metabolize lactose, whereas this number is below 10% in South-East Asia. 3,4 Unmetabolized lactose in the gut serves as food for resident microbes, and the consequence is symptoms like flatulence, abdominal pain, and diarrhea, 2 which explains why most people that are unable to metabolize lactose simply avoid dairy products and foods containing lactose, 4,5 which is unfortunate, as milk and dairy are highly nutritious foods. To provide an example of the latter, milk contains enough nutrients to sustain the life of mammals in their first critical period of life. ...
Streptococcus thermophilus is a fast-growing lactic acid bacterium (LAB) used in yoghurt and cheese manufacturing. Recently, we reported how this bacterium could serve as a cell catalyst for hydrolyzing lactose when permeabilized by nisin A. To enhance the lactose hydrolyzing activity of S. thermophilus, we mutated a dairy strain and screened for variants with elevated β-galactosidase activity. Two isolates, ST30-8 and ST95, had 2.4-fold higher activity. Surprisingly, both strains were able to hydrolyze lactose when used as whole-cell lactase catalysts without permeabilization, and ST30-8 hydrolyzed 30 g/L lactose in 6 h at 50 °C using 0.18 g/L cells. Moreover, both strains hydrolyzed lactose while growing in milk. Genome sequencing revealed a mutation in l-lactate dehydrogenase, which we believe hampers growth and increases the capacity of S. thermophilus to hydrolyze lactose. Our findings will allow production of sweet lactose-reduced yoghurt without the use of costly purified lactase enzymes.
... In addition, there has been an abundance of diagnostic research into tests such as the hydrogen breath test and lactose tolerance blood test enabling us to diagnose lactose intolerance quickly and easily. There are three types of lactose intolerance: alactasia, hypolactasia, and secondary lactase deficiency [7][8][9][10]. ...
... [2] Lactose malabsorption is the main cause of gastrointestinal symptoms among lactose intolerance sufferers. [3,4] Lactose malabsorption is a condition in which small intestine cannot digest or break down all the lactose persons eat or drink. Not everyone with lactose malabsorption has digestive symptoms after they consume lactose. ...
Background:
Lactose intolerance is defined as "Lactose malabsorption with gastrointestinal symptoms." Also, lactose malabsorption can be defined as "Not all ingested lactose was absorbed and that some has reached the large intestine." The common symptoms associated with the maldigestion of lactose are bloating, diarrhoea, nausea, and abdominal pain.
Aim:
The current study aims to assess knowledge of people awareness of the lactose intolerance disorder and its relation to nutrition and dietary habits in Saudi Arabia.
Methods:
A descriptive cross-sectional approach was used targeting all accessible population in Saudi Arabia aging 18 years or more and accept to participate in the study. Data were collected from participants using an online pre-structured questionnaire. The researchers constructed the survey tool after intensive literature review and expert's consultation. The questionnaire covered the following data: participants' socio-demographic data like age, gender, and monthly income. Second section covered participants' dairy products intake with associated symptoms. Third part covered personal and family history of glucose intolerance disorder among the study participants. Awareness was assessed using multiple repose and mutually exclusive questions.
Results:
A total of 1189 participants fulfilling the inclusion criteria completed the study questionnaire. Participants ages ranged from 18 to 58 years old with mean age of 25.1 ± 12.9 years. Exact of 692 (58.2%) participants were females. Exact of 104 (8.7%) of the study participants reported that they had lactose intolerance disorder which started at the age of 11 to 20 years among 41 (39.4%) and at the age of 21 to 30 years among 36 (34.6%). About 77% of the study participants know that lactose indolence disorder symptoms appear after eating dairy or its derivatives. A total of 45.8% reported that leaky gut syndrome (diarrhoea and bloating) is caused by symptoms that occur with lactose intolerance and 39.4% know lactose intolerance is an uncurable disease.
Conclusion:
In conclusion, this study revealed that nearly one out of each three persons on Saudi Arabia is knowledgeable regarding lactose intolerance disorder and its related factors and relieving factors. Dairy products use in daily basis was reported among two thirds of the study population with abdominal distention and abdominal pain was the main accompanying symptoms.
... Given increasing incidences of lactose intolerance, one of the most common digestive tract disorders, the enzymatic hydrolysis of in situ lactose in milk and milk-derived products, is highly desirable (Saqib et al. 2017). In fact, about 70% of the adults in the world are believed to be affected by lactose intolerance at different scales (Ugidos-Rodríguez et al. 2018). The hydrolysis of lactose in milk products becomes crucial because of unwanted lactose crystallization in ice cream during freezing. ...
A novel β-galactosidase gene (galM) was cloned from an aquatic habitat metagenome. The analysis of its translated sequence (GalM) revealed its phylogenetic closeness towards Verrucomicrobia sp. The sequence comparison and homology structure analysis designated it a member of GH42 family. The three-dimensional homology model of GalM depicted a typical (β/α)8 TIM-barrel containing the catalytic core. The gene (galM) was expressed in a heterologous host, Escherichia coli, and the purified protein (GalM) was subjected to biochemical characterization. It displayed β-galactosidase activity in a wide range of pH (2.0 to 9.0) and temperature (4 to 60 °C). The heat exposed protein showed considerable stability at 40 and 50 °C, with the half-life of about 100 h and 35 h, respectively. The presence of Na, Mg, K, Ca, and Mn metals was favorable to the catalytic efficiency of GalM, which is a desirable catalytic feature, as these metals exist in milk. It showed remarkable tolerance of glucose and galactose in the reaction. Furthermore, GalM discerned transglycosylation activity that is useful in galacto-oligosaccharides’ production. These biochemical properties specify the suitability of this biocatalyst for milk and whey processing applications.
Key points
• A novel β-galactosidase gene was identified and characterized from an aquatic habitat.
• It was active in extreme acidic to mild alkaline pH and at cold to moderate temperatures.
• The β-galactosidase was capable to hydrolyze lactose in milk and whey.
... The detection limit was as low as 30 nmol/L, which was nearly 30-fold lower than that of AuNCs (0.96 μmol/L). Furthermore, due to the efficient cellular internalization, prominent luminescence and Lactose intolerance is a typical genotype related with functional lactose deficiency [88]. Thus, lactose-free products have aroused great interest, promoting the demand to detect trace lactose in relative products. ...
Gold nanoclusters (AuNCs) are an emerging type of ultrasmall nanomaterials possessing unique physicochemical characteristics. Metal-organic frameworks (MOFs), a singular kind of porous solid and crystalline material, have attracted tremendous attention in recent years. The combination of AuNCs and MOFs can integrate and improve the prominent properties of both components, such as high catalytic activities, tunable optical properties, good biocompatibility, surface functionality and stability, which make the composites of MOFs and AuNCs promising for sensing applications. This review systematically summarizes the recent progress on the sensing of various analytes via MOFs-mediated AuNCs assemblies based on strategies of luminescence sensing, colorimetric sensing, electrochemiluminescence sensing, and electrochemical and photoelectrochemical sensing. A brief outlook regarding the future development of MOFs-mediated AuNCs assemblies for sensing application is presented as well.
... Previous research [20] has pointed out that vascular endothelial injury and inflammatory reaction are important causes of CVS after aSAH. The main reason is that after receiving physical and chemical stimulation, vascular endothelial cells can exert the biological effects of regulating vascular tension, inhibiting thrombosis and controlling vascular growth through synthesis and secretion of various vasoactive substances [21]. ...
Objective:
Aneurysmal subarachnoid hemorrhage (aSAH) is an acute disease with rapid progression and critical condition. The most common complication of aSAH is cerebral vasospasm (CVS). Patients are predisposed to severe cerebral ischemia, brain injury, or even death if effective measures are not taken in time to relieve symptoms. This study mainly determines the effect of nimodipine (NM) combined with fasudil on vascular endothelial function (VEF) and inflammatory factors (IFs) in patients with aSAH induced CVS.
Methods:
The clinical data of 77 patients with aSAH induced CVS treated in the Renmin Hospital of Wuhan University from March 2019 to June 2020 were analyzed retrospectively. Based on different drug therapies, patients receiving NM monotherapy were assigned to the control group (n=32), while those treated with NM combined with fasudil were included in the observation group (n=45), both received two consecutive weeks of treatment. The two arms were compared regarding the following items: clinical efficacy, average blood flow velocities (BFVs) of anterior, posterior and middle cerebral arteries, serum IFs, levels of vascular endothelial growth factor (VEGF), ET-1 and CGRP, cognitive function (Montreal Cognitive Assessment Scale, MOCA), activities of daily living (Bathel index), and adverse reactions.
Results:
The overall response rate of the observation group was significantly higher than that of the control group (P<0.05). After treatment, the BFVs of the anterior, posterior and middle cerebral arteries in the observation group decreased significantly compared with the control group (P<0.05). ET-1 and VEGF decreased in both groups, while CGRP increased, with more significant changes in the observation group (P<0.05). Serum IFs reduced in both arms, with more evident reductions in the observation group (P<0.05). The MOCA score and Barthel index increased statistically in both arms and were higher in the observation group compared with the control group (P<0.05). There was no significant difference in the total incidence of adverse reactions between the observation group and the control group (P>0.05).
Conclusions:
NM combined with fasudil in the treatment of aSAH induced CVS can effectively improve the VEF, alleviate IFs, and enhance the cognitive function and quality of life of patients, which is worth popularizing in clinic.
... For individuals with SNP variants that suppress β-lactase expression after infancy, lactose is minimally digested in the small intestine. Instead, lactose enters the large intestine where its rapid fermentation may result in the acute adverse gastrointestinal (GI) events that are symptomatically typical of lactose intolerance [2,4]. However, this is not the only form of dairy intolerance that may be experienced. ...
Background/objectives
Self-reported digestive intolerance to dairy foods is common. As dairy can be an important source of dietary protein, this study aimed to identify whether milk protein digestion is compromised in individuals with digestive intolerance.
Subjects/methods
Adult women (n = 40) were enroled in this double-blinded, randomised cross-over trial, with digestive symptoms characterised using a lactose challenge and self-reported digestive symptom questionnaire. Participants were classified as either lactose intolerant (LI, n = 10), non-lactose dairy intolerant (NLDI, n = 20) or dairy tolerant (DT, n = 10). In a randomised sequence, participants consumed three different kinds of milk (750 ml); conventional milk (CON), a2 Milk™ (A2M), and lactose-free conventional milk (LF-CON). Circulatory plasma amino acid (AA) concentrations were measured at baseline and every 30 min until 3 h post-ingestion.
Results
In all participants across all milk types, plasma AA concentrations (AUC0-180) increased after milk ingestion with no significant differences in responses observed between milk types or participants (P > 0.05), with the exception of the suppressed lysine response in the DT group following A2M ingestion, relative to the other two groups and milk types (P < 0.05).
Conclusion
Milk protein digestion, as determined by circulatory AAs, is largely unaffected by dairy- and lactose- intolerances.
... Lactose is a disaccharide composed of two aldohexoses, chemically defined as O-β-D-galactopyranosyl-(1-4)-β-D-glucose, which is soluble in water (170 g/L at 15 • C) and six times less sweet than sucrose [1]. As lactose is the primary carbohydrate source found in most mammalian milks, it is essential for the development of neonatal mammals, due to the appropriate balance of glucose and galactose provided by its molecule. ...
Much attention has recently been paid to β-Galactosidases (β-D-galactoside galactohidrolase; EC 3.2.1.23), commonly known as lactases, due to the lactose intolerance of the human population and the importance of dairy products in the human diet. This enzyme, produced by microorganisms, is being used in the dairy industry for hydrolyzing the lactose found in milk to produce lactose-free milk (LFM). Conventionally, β-galactosidases catalyze the hydrolysis of lactose to produce glucose and galactose in LFM; however, they can also catalyze transgalactosylation reactions that produce a wide range of galactooligosaccharides (GOS), which are functional prebiotic molecules that confer health benefits to human health. In this field, different works aims to identify novel microbial sources of β-galactosidase for removing lactose from milk with the relative GOS production. Lactase extracted from thermophilic microorganisms seems to be more suitable for the transgalactosylation process at relatively high temperatures, as it inhibits microbial contamination. Different immobilization methods, such as adsorption, covalent attachment, chemical aggregation, entrapment and micro-encapsulation, have been used to synthesize lactose-derived oligosaccharides with immobilized β-galactosidases. In this mini-review, particular emphasis has been given to the immobilization techniques and bioreactor configurations developed for GOS synthesis in milk, in order to provide a more detailed overview of the biocatalytic production of milk oligosaccharides at industrial level.
... Therefore, the lower blood pH and bicarbonate concentration and the high AG values identified in diarrheic compared to healthy calves was likely due to increased absorption of D-and L-lactate from the lumen of the gastrointestinal tract. The main source of energy and carbohydrates in cow milk is lactose, which is hydrolyzed by lactase in the small intestine to glucose and galactose (44). Lactase is produced and secreted at the brush border of the small intestine (45). ...
Diarrhea is the leading cause of morbidity, mortality and antimicrobial drug use in calves during the first month of age. Alteration in the bacterial communities of the gastrointestinal tract occurs during diarrhea. Diarrheic calves often develop anion gap (AG) acidosis associated with increased concentrations of unmeasured anions including D-and L-lactate. However, studies investigating the association between gut microbiota alterations and the development of acid-base disorders in diarrheic calves are lacking. We investigated the fecal bacterial alterations of calves with diarrhea and its association with changes in blood pH, and AG. Blood and fecal samples from healthy and diarrheic veal calves were taken 7 days after arrival to the farm. The fecal microbiota of healthy and diarrheic calves was assessed by sequencing of 16S ribosomal RNA gene amplicons. Blood gas analysis was completed using an i-Stat analyzer. In healthy calves, higher richness, evenness, and diversity were observed compared to diarrheic calves. Phocaeicola, Bacteroides, Prevotella, Faecalibacterium, Butyricicoccus, Ruminococcaceae and Lachnospiraceae were enriched in healthy compared with diarrheic calves. Enterococcus, Ligilactobacillus, Lactobacilus, Gallibacterium Streptococcus, and Escherichia/Shigella were enriched in diarrheic calves. In diarrheic calves, an increased abundance of lactate-producing bacteria including Lactobacillus, Streptococcus, Veillonella, Ligilactobacillus and Olsenella was detected. Diarrheic calves had a lower pH and bicarbonate concentration and a higher AG concentration than healthy calves. Together, these results indicate that calf diarrhea is associated with a shift from obligated to facultative anaerobes and expansion of lactate-producing bacteria which are related to acidemia, low bicarbonate and increase AG. Our results highlight the importance of the gastrointestinal microbiota on the clinicopathological changes observed in diarrheic calves.
Lactose intolerance-nutritional risk of calcium deficiency? STRESZCZENIE Wstęp. Nietolerancja laktozy, to schorzenie, które dotyka coraz większą liczbę popula-cji. Prawidłowo skomponowana dieta stanowi ważny czynnik leczenia tego schorzenia. Nieodpowiednio zbilansowana dieta bezlaktozowa może prowadzić do poważnych kon-sekwencji zdrowotnych. Celem pracy była ocena wiedzy osób z nietolerancją laktozy na temat konsekwencji związanych z eliminacją produktów nabiałowych z diety. Materiał i metody. Badanie zostało przeprowadzone w mediach społecznościach w zamkniętych grupach wśród osób z nietolerancją laktozy. Dane zebrano na przełomie 2021 oraz 2022 roku na podstawie autorskiego kwestionariusza. Dodatkowo na potrzeby badania stworzono skalę oceny. Za prawidłowo wypełnioną ankietę można było zdobyć maksymalnie 30 punktów. Wyniki. Po zsumowaniu punktów przyznanych za prawidłowe odpowiedzi respondenci średnio otrzymali 15 punktów. Obszarami wiedzy, w których respondenci wykazali się największą znajomością, były pytania dotyczące żywieniowych źródeł wapnia oraz kon-sekwencji jego niedoboru w diecie. Obszarami, w których respondenci nie posiadali dostatecznej wiedzy, była zawartość laktozy w produktach spożywczych oraz bezlakto-zowych źródeł wapnia. W części oceniającej nawyki żywieniowe respondenci przyznali, że nie mają nawyku wdrażania dodatkowej suplementacji wapnia. Wnioski. Poziom wiedzy na temat żywienia w nietolerancji laktozy wśród osób z tym scho-rzeniem został oceniony jako niski. Zaobserwowano, że badani znają żywieniowe źródło wapnia, są świadomi konsekwencji związanych z jego niedoborem w diecie, natomiast nie wdrażają dodatkowej suplementacji. Działaniami jakie należy podjąć, aby poszerzyć ich wiedzę w tym zakresie jest podejmowanie edukacji żywieniowej. Forum Medycyny Rodzinnej 2023, tom 17, nr 2, 87-98 Słowa kluczowe: laktoza, nietolerancja laktozy, wapń, bez laktozy, dieta bezlaktozowa ABSTRACT Introduction. Lactose intolerance is a disease that affects an increasing number
Cold-adapted enzymes, produced in cold-adapted organisms, are a class of enzyme with catalytic activity at low temperatures, high temperature sensitivity, and the ability to adapt to cold stimulation. These enzymes are largely derived from animals, plants, and microorganisms in polar areas, mountains, and the deep sea. With the rapid development of modern biotechnology, cold-adapted enzymes have been implemented in human and other animal food production, the protection and restoration of environments, and fundamental biological research, among other areas. Cold-adapted enzymes derived from microorganisms have attracted much attention because of their short production cycles, high yield, and simple separation and purification, compared with cold-adapted enzymes derived from plants and animals. In this review we discuss various types of cold-adapted enzyme from cold-adapted microorganisms, along with associated applications, catalytic mechanisms, and molecular modification methods, to establish foundation for the theoretical research and application of cold-adapted enzymes.
Cow's milk has served as a crucial part of the human diet for ages due to its nutritional benefits. However, in recent years, non-dairy milk alternatives (NDMAs) have surpassed cow's milk in its popularity due to different issues associated with cow's milk consumption. Although NDMAs contain additives, sweeteners, are deficient in good quality protein and entail a lack bioavailability of nutrients, they make for an appealing choice of consumers since they are a good source of bioactive components and carry a healthy fatty acid profile. Despite their popularity, there are concerns regarding their commercialization, as they lack stability upon storage and standardized technology for their large-scale production. The problems present a broad field for both the food industry and researchers to work synergistically in developing novel milk alternatives that are wholesome, healthy, cost-effective, and have better techno-functionality. This review comprehensively assesses the current scenario, health aspects, and production technologies in developing NDMAs, considering the accompanying challenges and promising prospects.
Prebiotics are important components in functional foods. Galacto-oligosaccharides (GOS) are nondigestible oligosaccharides whose prebiotic condition has been conclusively proven. GOS are produced from lactose, which is a cheap commodity, usually in surplus from the cheese manufacturing industry. GOS synthesis is catalyzed by β-galactosidases that are cheap enzymes with a long record of use in the food industry for the production of low-lactose milk and dairies, so its use for GOS synthesis represents a remarkable technological opportunity. GOS have salient features that make them ideal for their incorporation into functional foods, especially in dairy products, so that a scheme of circular economy can be envisaged. Even though GOS production is well established at industrial level, several challenges remain that are related to the rather low yield of the kinetically controlled reaction of synthesis from lactose. This results in poor substrate utilization and complex downstream operations, so major efforts are devoted to developing better suited enzymes and cheaper and simpler downstream operations. This chapter focuses on GOS production within the framework of functional foods, with special emphasis on technological perspectives of their production, but basic aspects, like reaction mechanisms and mode of prebiotic action, are also revised.
Modern consumer expectations have become highly diversified: they want more opportunities to meet diverse family needs (diversity of family members in age, gender, physical activity, etc. ,) and individual health goals with a huge variety of sensorial preferences. Our research is aimed to develop a protein-dense, highly bioactive, lactose- and whey protein-free beverage applying a central composite rotational design (CCRD) with 2 factors. For this purpose, an egg white-based beverage was flavored with mixed berries (factor A) and enriched with bovine collagen peptides (factor B). After suitable sample preparation, the rheological properties were investigated by an Anton Paar MCR 92 rheometer (with CC 27 system, and flow behavior was analyzed with a Herschel-Bulkley (H-B) model). The antioxidant capacity of samples was investigated by Ferric Reducing Antioxidant Power (FRAP) method, the total anthocyanin content was estimated based on a spectrophotometric method, and the total phenolic content was determined by the Folin Ciocalteu method. Our results are figured on response surfaces demonstrating that both factors and their interactions show a positive correlation with the examined parameters. Based on the CCRD, all investigated parameters are significantly influenced by at least one aspect and can be adequately estimated for further product development.
Plant-based beverages are gaining popularity among consumers who are seeking alternative and environmentally sustainable options to traditional dairy drinks. The food industry is therefore developing a range of affordable, convenient, desirable, nutritional, and sustainable plant-based milk alternatives. This chapter provides an overview of the current knowledge on fundamental processing steps to convert plant material into plant-based beverages, what are processing challenges for different plant sources, how to overcome these challenges and potential quality deficiencies, and what are the opportunities to maximize textural, nutritional, and sensory aspects of plant-based beverages.
Fucosyllactose (FL) has garnered considerable attention for its benefits on infant health. In this study, we report an efficient E. coli cell factory to produce 2'/3-fucosyllactose (2'/3-FL) with lactose de novo pathway through metabolic network remodeling, including (1) modification of the PTSGlc system to enhance glucose internalization efficiency; (2) screening for β-1,4-galactosyltransferase (β-1,4-GalT) and introduction of lactose synthesis pathway; (3) eliminating inhibition of byproduct pathways; (4) constructing antibiotic-free and inducer-free FL strains; and (5) up-regulating the expression of genes in the GDP-l-fucose module. The final engineered strains BP10-3 and BP11-3 produced 4.36 g/L for 2'-FL and 3.23 g/L for 3-FL in shake flasks. In 3 L bioreactors, fed-batch cultivations of the two strains produced 40.44 g/L for 2'-FL and 30.42 g/L for 3-FL, yielding 0.63 and 0.69 g/g glucose, respectively. The strategy described in this work will help to engineer E. coli as a safe chassis for other lactose-independent HMOs production.
The odour, particle size distribution, microstructure and nutrient profile of giant panda milk (GPM) was compared with bovine milk (BM) and caprine milk (CM). SDS-PAGE images of GPM showed clear, deep and uncertain bands different from those for BM and CM. GPM displayed significantly higher levels for free amino acids (p < 0.05), as well as more polyunsaturated and monounsaturated fatty acids. An electronic nose distinguished the three samples; GPM had the strongest response values to sensors. The effective diameter and polydispersity index of GPM were significantly higher than BM and CM (p < 0.05), and the same results were also observed in confocal laser scanning microscopy (CLSM) images. A giant panda milk substitute formulation with the following main nutrients is recommended: protein, 36%; fat, 50%; carbohydrates, 8%. It is also necessary to supplement a small quantity of isoglobotriose, and adjust the milk substitute amino acids and fatty acids ratios.
There is an increasing trend today towards plant-based diets in western society, often resulting in milk restriction. In the case of very young children, the direct substitution of milk by other foods, without proper nutritional advice, may lead to a lack of nutrients and hence to growth and development alterations. This study focuses on the nutritional assessment of various commercially available plant-based drinks, to determine their adequacy as alternatives to ruminant milk, in relation to the nutritional requirements of toddlers (1–3 years old), and to establish whether other sources of nutrient supplementation may be needed, as well as any other possible positive and /or negative health effects associated to their consumption. A sample of 179 commercial plant-based drinks (almond, coconut, hemp, oat, rice, soy, tigernut) were chosen and their nutrient contents were compared to the EFSA nutrient reference values for toddlers. The scientific literature on the presence of bioactive and/or undesirable compounds was reviewed.
None of the plant-based drinks studied should be considered as a milk substitute, since they are different food products with a different composition. However, from the results obtained, the best choice for toddlers who do not consume milk would be to consume at least 250 mL/day of fortified soy drink (for its higher amount and quality of protein, polyunsaturated fatty acids and phytosterols), and always in the context of a carefully-balanced diet. Almond, hemp or oat drinks are other alternatives that can be used in combination or for soy-allergic toddlers.
The key nutrients that should be fortified in plant-based drinks are: vitamins A and B12, calcium, zinc and iodine, as they represent the most significant nutritional differences with milk; vitamin D would also be desirable. Of these, vitamins A, B12, D and calcium, are easily found in many commercial plant-based drinks on the Spanish market (most frequently in soy drinks), unlike iodine and zinc, which were not added to any. Given the fish restriction in vegetarians/vegans and the fact that plant-based drinks provide high amounts of phytates and tannins, which act as antinutrients, a good strategy for the industry would be to fortify plant-based drinks with iodine and zinc to improve the nutritional value of products aimed to vegetarians/vegans.
This study aimed to investigate the activity of lactase immobilized polycaprolactone and silk fibroin (PCL/SF)-based nanofiber and nitrocellulose membrane for the preparation of lactose-reduced milk. PCL/SF -based nanofiber was prepared by using the electrospinning method. The lactase enzyme was immobilized using the physical adsorption method on both surfaces, and then the optimum operating temperature and pH of the immobilized enzymes were determined. The efficiency of the immobilized lactase enzyme was determined in both goat and cow milk. The nutrient content of milk was also analyzed before and after the incubation of nanofiber and membrane with milk. The lactose hydrolysis efficiency of the lactase immobilized nitrocellulose membrane was found to be higher than the lactase immobilized PCL/SF -based nanofiber. Lactose was hydrolyzed 59% in cow milk and 87% in goat milk by using lactase immobilized nitrocellulose membrane. 42% of lactose was also hydrolyzed in cow milk and 21% was hydrolyzed in goat milk by using lactase immobilized PCL/SF-based nanofiber. However, the use of these two bioactive surfaces did not change the fat and protein composition of both cow and goat milk. In conclusion, lactase immobilized nitrocellulose membrane was found to be more advantageous in the production of lactose-reduced milk than the lactase immobilized polycaprolactone/silk fibroin nanofiber.
The study aimed at evaluation of β-galactosidase activity for lactose hydrolysis (DH) and galactooligosaccharide (GOS) formation at 7 °C. β-galactosidase derived from K. lactis was more effective than B. lichenformis for DH and GOS formation in 16 % lactose solution. β-galactosidase from K. lactis exhibited 96.61 % DH and 7.28 % GOS production after 12 h of reaction and hence was utilized for lactose hydrolysis in concentrated skim milk (40 % total solids). Use of 9.53 U/mL enzyme resulted in significantly high DH (97.06 %) after 12 h with 4.90 g/L of residual lactose. However, maximum GOS formation of 12.01 % with 94.74 % DH was obtained after 4 h. Further increase in reaction time up to 12 h resulted in breakdown of tri and tetrasaccharide GOS, thereby, reducing GOS content. Hence, reaction time of 12 h was finalized to obtain maximum DH along with additional benefit of GOS formation.
Portable 3D printing biosensing devices have great potential as rapid detection and analytical platforms due to their unique characteristics such as high precision and low cost. In this study, a method for rapid determination of lactose in milk was developed based on bioactive paper-3D printing integration technology. The bioactive paper was prepared by combining three enzymes cascade system composed of β -galactosidase, glucose oxidase and Fe-N-C nanozyme (with excellent peroxidase-like activity and superior affinity). In the presence of lactose, the test paper changed from colorless to blue under the condition of TMB, which can be identified by naked eye. With the help of portable chromometer and smart phone, the RGB color index was analyzed and quantified. The entire detection process can be integrated into the 3D printing device that we have designed and completed in 25 min, with the detection limits of qualitative and quantitative were 0.04 g 100 g⁻¹ and 5.61 μg 100 g⁻¹, which could simultaneously satisfy the detection requirements of rapid, sensitive and portable operation. The bioactive paper and 3D printing device are long shelf life (six months) and cost-effective, which means this integration technology has a good application prospect in areas lacking experimental conditions.
This study assesses an educational intervention aimed at the enhancement of the learning of genetics related to the expression of genetic information and protein synthesis. For this purpose, a pretest and a posttest were completed by 43 students in the 10th grade, organized into an experimental and a control group. For the experimental group, an educational intervention was designed, addressing genetics in an observable and familiar context related to lactose intolerance. In the control group, these contents were addressed by means of more theoretical transmission of knowledge. Differences between the tests and groups were analyzed. In the pretest, the ideas in both groups were very similar, without statistically significant differences. In the posttest, both interventions seemed to be adequate for improving the students’ understanding of descriptive aspects, such as the location of genetic information. On the other hand, for those aspects which require greater systemic vision, to relate nutrition and protein synthesis, the experimental group obtained better results. Nevertheless, difficulties regarding the understanding of the transcription of DNA into RNA still remain, and their educational implications need to be discussed.KeywordsEducational interventionDaily problemGeneticsLactase synthesisSecondary school
Intolerance to carbohydrates is relatively common in childhood, but still poorly recognized and managed. Over recent years it has come to the forefront because of progresses in our knowledge on the mechanisms and treatment of these conditions. Children with intolerance to carbohydrates often present with unexplained signs and symptoms. Here, we examine the most up-to-date research on these intolerances, discuss controversies relating to the diagnostic approach, including the role of molecular analysis, and provide new insights into modern management in the pediatric age, including the most recent evidence for correct dietary treatment.
Background
The expression of lactase which digests lactose from milk in humans is generally lost after weaning, but selected mutations influencing the promoter of the lactase gene have spread into the human populations. This is considered a classical example of gene-culture co-evolution, and several studies suggested that the lactase gene has been under strong directional evolutionary selective pressure in the past 5000 to 10,000 years.
Results
In the present study we investigated the distribution of three gene variants leading to lactase persistence in 12 different East African populations as well as one European population. Our results show that with the exception of Copts and Nilotic populations who are fully lactose non-persistent, the majority of populations of East Africa show at least partly lactose persistence, with both ethnic and socio-economic aspects playing an important role in the distribution of genetic variants. In this study, the variants C/G-13907 and T/G-13915, which are the major variants among the nomadic Arabs in the Arabia and Beja of East Africa, showed remarkable frequencies in Sudanese populations, especially those of pastoralists, in line with the historical links and bidirectional migration of nomadic populations between Arabia and East Africa. The C/T-13910 variant, generally associated with European populations is uniquely present among the Fulani.
Conclusions
These data indicate that a combination of socio-economic, ethnic and evolutionary factors converged to shape the genetic structure of lactase persistence in East African populations.
Electronic supplementary material
The online version of this article (doi:10.1186/s13104-015-1833-1) contains supplementary material, which is available to authorized users.
Lactose intolerance related to primary or secondary lactase deficiency is characterized by abdominal pain and distension, borborygmi, flatus, and diarrhea induced by lactose in dairy products. The biological mechanism and lactose malabsorption is established and several investigations are available, including genetic, endoscopic and physiological tests. Lactose intolerance depends not only on the expression of lactase but also on the dose of lactose, intestinal flora, gastrointestinal motility, small intestinal bacterial overgrowth and sensitivity of the gastrointestinal tract to the generation of gas and other fermentation products of lactose digestion. Treatment of lactose intolerance can include lactose-reduced diet and enzyme replacement. This is effective if symptoms are only related to dairy products; however, lactose intolerance can be part of a wider intolerance to variably absorbed, fermentable oligo-, di-, monosaccharides and polyols (FODMAPs). This is present in at least half of patients with irritable bowel syndrome (IBS) and this group requires not only restriction of lactose intake but also a low FODMAP diet to improve gastrointestinal complaints. The long-term effects of a dairy-free, low FODMAPs diet on nutritional health and the fecal microbiome are not well defined. This review summarizes recent advances in our understanding of the genetic basis, biological mechanism, diagnosis and dietary management of lactose intolerance.
Humans learned to exploit ruminants as a source of milk about 10,000 years
ago. Since then, the use of domesticated ruminants as a source of milk and dairy products
has expanded until today when the dairy industry has become one of the largest sectors
in the modern food industry, including the spread at the present time to countries such
as China and Japan. This review analyzes the reasons for this expansion and flourishing.
As reviewed in detail, milk has numerous nutritional advantages, most important being
almost an irreplaceable source of dietary calcium, hence justifying the effort required
to increase its consumption. On the other hand, widespread lactose intolerance among
the adult population is a considerable drawback to dairy-based foods consumption. Over
the centuries, three factors allowed humans to overcome limitations imposed by lactose
intolerance: (i) mutations, which occurred in particular populations, most notably in the north European Celtic societies and African nomads, in which carriers of the lactose
intolerance gene converted from being lactose intolerant to lactose tolerant; (ii) the ability
to develop low-lactose products such as cheese and yogurt; and (iii) colon microbiome
adaptation, which allow lactose intolerant individuals to overcome its intolerance. However,
in a few examples in the last decade, modern dairy products, such as the popular and
widespread bio-cultured yogurts, were suspected to be unsuitable for lactose intolerant
peoples. In addition, the use of lactose and milk-derived products containing lactose in non-dairy products has become widespread. For these reasons, it is concluded that it might
be important and helpful to label food that may contain lactose because such information will
allow lactose intolerant groups to control lactose intake within the physiological limitations
of approx. 12 g per a single meal.
Lactase-phlorizin hydrolase (LPH) is a membrane glycoprotein and the only β-galactosidase of the brush border membrane of the intestinal epithelium. Besides active transcription, expression of the active LPH requires different maturation steps of the polypeptide through the secretory pathway, including N- and O-glycosylation, dimerization and proteolytic cleavage steps. The inability to digest lactose due to insufficient lactase activity results in gastrointestinal symptoms known as lactose intolerance. In this review, we will concentrate on the structural and functional features of LPH protein and summarize the cellular and molecular mechanism required for its maturation and trafficking. Then, different types of lactose intolerance are discussed, and the molecular aspects of lactase persistence/non-persistence phenotypes are investigated. Finally, we will review the literature focusing on the lactase persistence/non-persistence populations as a comparative model in order to determine the protective or adverse effects of milk and dairy foods on the incidence of colorectal, ovarian and prostate cancers.
Abstract A growing number of consumers opt for plant based milk substitutes for medical reasons or as a lifestyle choice. Medical reasons include lactose intolerance with a worldwide prevalence of 75% and cow's milk allergy. Also in countries where mammal milk is scarce and expensive, plant milk substitutes serve as a more affordable option. However many of these products have sensory characteristics objectionable to the mainstream Western palate. Technologically, plant milk substitutes are suspensions of dissolved and disintegrated plant material in water, resembling cow's milk in appearance. They are manufactured by extracting the plant material in water, separating the liquid and formulating the final product. Homogenisation and thermal treatments are necessary to improve the suspension and microbial stabilities of commercial products that can be consumed as such or be further processed into fermented dairy type products. The nutritional properties depend on the plant source, processing and fortification. As some products have extremely low protein and calcium contents, consumer awareness is important when plant milk substitutes are used to replace cow's milk in the diet e.g. in the case of dairy intolerances. If formulated into palatable and nutritionally adequate products, plant based substitutes can offer a sustainable alternative to dairy products.
The scientific advances related to healthy properties of the probiotics have increased in a significant form. It is evident the positive effects on physiological functions. Considering the relevance in these advances, this review presents a summary of the scientific evidence supporting the principal biological effects of the probiotics in digestive function, systemic immune reply and lipid profile, pathologies relevant in the functional food development.
Background:
symptoms attributed to the lactose intolerance are an important public health issue because of their prevalence and social relevance. Also because they may cause undue rejection of dairy products consume with potential health consequences. Transit time is a putative factor implied in the severity of symptoms associated with lactose.
Objectives:
to elucidate the relation between orocecal transit time (OCTT) and lactose intolerance symptoms.
Methods:
observational study in patients referred to a lactose hydrogen breath test who showed an increase in breath H2 excretion higher than 25 ppm. OCTT was measured with the breath test and symptoms of lactose tolerance with a validated scale. Symptoms were measured twice: before receiving the lactose, inquiring about self perceived symptoms when patients consumed dairy products at home ("home symptoms"), and again after completing the lactose breath test ("test symptoms").
Results:
161 patients were included. There was no correlation between OCTT and home symptoms (r = -0.1). When OCTT was faster than 60 minutes, intensity of "test symptoms" was similar to "home symptoms". However, in patients with normal or slow OCTT, the "home symptoms" were more intense than the "test symptoms" (p < 0.05). At home, symptoms were independent of OCTT but with the lactose test load the symptoms were proportionately more intense with faster OCTT.
Conclusions:
in lactose maldigesters, selfreported symptoms of lactose intolerance are more pronounced at home than after a high lactose challenge. Intolerance symptoms that patients attributed to lactose consume at home are due to factors other than fast OCTT.
Adult-type hypolactasia, also known as lactase non-persistence (lactose intolerance), is a common autosomal recessive condition resulting from the physiological decline in activity of the lactase-phlorizin hydrolase (LPH) in intestinal cells after weaning. LPH hydrolyzes lactose into glucose and galactose. Sequence analyses of the coding and promoter regions of LCT, the gene encoding LPH, has revealed no DNA variations correlating with lactase non-persistence. An associated haplotype spanning LCT, as well as a distinct difference in the transcript levels of 'non-persistence' and 'persistence' alleles in heterozygotes, suggest that a cis-acting element contributes to the lactase non-persistence phenotype. Using linkage disequilibrium (LD) and haplotype analysis of nine extended Finnish families, we restricted the locus to a 47-kb interval on 2q21. Sequence analysis of the complete region and subsequent association analyses revealed that a DNA variant, C/T-13910, roughly 14 kb upstream from the LCT locus, completely associates with biochemically verified lactase non-persistence in Finnish families and a sample set of 236 individuals from four different populations. A second variant, G/A-22018, 8 kb telomeric to C/T-13910, is also associated with the trait in 229 of 236 cases. Prevalence of the C/T-13910 variant in 1,047 DNA samples is consistent with the reported prevalence of adult-type hypolactasia in four different populations. That the variant (C/T-13910) occurs in distantly related populations indicates that it is very old.
Milk from domestic cows has been a valuable food source for over 8,000 years, especially in lactose-tolerant human societies that exploit dairy breeds. We studied geographic patterns of variation in genes encoding the six most important milk proteins in 70 native European cattle breeds. We found substantial geographic coincidence between high diversity in cattle milk genes, locations of the European Neolithic cattle farming sites (>5,000 years ago) and present-day lactose tolerance in Europeans. This suggests a gene-culture coevolution between cattle and humans.
In recent years, numerous studies have been published on the health effects of yogurt and the bacterial cultures used in the production of yogurt. In the United States, these lactic acid-producing bacteria (LAB) include Lactobacillus and Streptococcus species. The benefits of yogurt and LAB on gastrointestinal health have been investigated in animal models and, occasionally, in human subjects. Some studies using yogurt, individual LAB species, or both showed promising health benefits for certain gastrointestinal conditions, including lactose intolerance, constipation, diarrheal diseases, colon cancer, inflammatory bowel disease, Helicobacter pylori infection, and allergies. Patients with any of these conditions could possibly benefit from the consumption of yogurt. The benefits of yogurt consumption to gastrointestinal function are most likely due to effects mediated through the gut microflora, bowel transit, and enhancement of gastrointestinal innate and adaptive immune responses. Although substantial evidence currently exists to support a beneficial effect of yogurt consumption on gastrointestinal health, there is inconsistency in reported results, which may be due to differences in the strains of LAB used, in routes of administration, or in investigational procedures or to the lack of objective definition of "gut health." Further well-designed, controlled human studies of adequate duration are needed to confirm or extend these findings.
The results of our previous study suggested that in addition to the small intestinal lactase activity and transit time, colonic processing of lactose may play a role in lactose intolerance. We investigated whether colonic fermentation of lactose is correlated with lactose intolerance. After 28 Chinese subjects had undergone 1 glucose (placebo) and 2 lactose challenges, consistent lactose tolerant (n = 7) and intolerant (n = 5) subjects with no complaints after glucose administration were classified on the basis of the 6-h symptom scores. Before the challenges, fecal samples were collected for in vitro incubation with lactose. The incubation was carried out in a static system under anaerobic conditions for 5 h during which samples were taken for measurement of short-chain fatty acids, lactate, lactose, glucose, and galactose. Fecal bacterial composition was determined by fluorescent in situ hybridization. The tolerant and intolerant groups did not differ in the rate or degree of hydrolysis of lactose or production of glucose and galactose. The intolerant group produced d- and l-lactate, acetate, propionate, and butyrate significantly faster than the tolerant group. In the intolerant group, the amounts of acetate, propionate, butyrate, and l-lactate produced were higher than those in the tolerant group. Fecal bacterial composition did not differ between the 2 groups. The results indicate that the degree and rate of lactose hydrolysis in the colon do not play a role in lactose intolerance. However, after lactose is hydrolyzed, a faster and higher production of microbial intermediate and end metabolites may be related to the occurrence of symptoms.
Lactose malabsorption is a very common condition characterized by intestinal lactase deficiency. Primary lactose malabsorption is an inherited deficit present in the majority of the world's population, while secondary hypolactasia can be the consequence of an intestinal disease. The presence of malabsorbed lactose in the colonic lumen causes gastrointestinal symptoms. The condition is known as lactose intolerance. In patients with lactase nonpersistence, treatment should be considered exclusively if intolerance symptoms are present. In the absence of guidelines, the common therapeutic approach tends to exclude milk and dairy products from the diet. However, this strategy may have serious nutritional disadvantages. Several studies have been carried out to find alternative approaches, such as exogenous beta-galactosidase, yogurt and probiotics for their bacterial lactase activity, pharmacological and non pharmacological strategies that can prolong contact time between enzyme and substrate delaying gastrointestinal transit time, and chronic lactose ingestion to enhance colonic adaptation. In this review the usefulness of these approaches is discussed and a therapeutic management with a flow chart is proposed.
The enzyme lactase that is located in the villus enterocytes of the small intestine is responsible for digestion of lactose in milk. Lactase activity is high and vital during infancy, but in most mammals, including most humans, lactase activity declines after the weaning phase. In other healthy humans, lactase activity persists at a high level throughout adult life, enabling them to digest lactose as adults. This dominantly inherited genetic trait is known as lactase persistence. The distribution of these different lactase phenotypes in human populations is highly variable and is controlled by a polymorphic element cis-acting to the lactase gene. A putative causal nucleotide change has been identified and occurs on the background of a very extended haplotype that is frequent in Northern Europeans, where lactase persistence is frequent. This single nucleotide polymorphism is located 14 kb upstream from the start of transcription of lactase in an intron of the adjacent gene MCM6. This change does not, however, explain all the variation in lactase expression.
This Opinion of the EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) deals with lactose thresholds in lactose intolerance and galactosaemia. LACTASE DEFICIENCY AND LACTOSE INTOLERANCE: Primary lactase deficiency, also referred to as lactase-nonpersistence (LNP), is genetically determined and a normal, developmental phenomenon characterised by the down-regulation of lactase activity. In adults with LNP, undigested lactose reaches the colon where it can elicit symptoms of lactose intolerance. Lactose tolerance varies widely among individuals with lactose maldigestion. A single threshold of lactose for all lactose intolerant subjects cannot be determined owing to the great variation in individual tolerances. Symptoms of lactose intolerance have been described after intake of less than 6 g of lactose in some subjects. The vast majority of subjects with lactose maldigestion will tolerate up to 12 g of lactose as a single dose with no or minor symptoms. Higher doses may be tolerated if distributed throughout the day. GALACTOSAEMIA: Galactosaemia is caused by three different genetic enzyme defects in the metabolism of galactose. Severe galactosaemia, if untreated, is accompanied by a potentially fatal impairment of hepatic and renal function and with cataracts in the newborn and the young infant. The dietetic principle in the management of all types of galactosaemia is the elimination of all sources of galactose, including human milk, as far as possible. Dietetic management is started with lactose free infant and later follow-on formulae with a lactose content ≤10 mg/100 kcal. In older infants, children and adults, foods containing milk or milk products or lactose as an ingredient must be avoided, as far as possible, so that the overall daily lactose intake will be about 25 mg/100 kcal. A precise threshold for galactose/lactose intake below which adverse effects are not elicited cannot be given.
The inability to digest lactose, due to lactase nonpersistence, is a common trait in adult mammals, except in certain human populations that exhibit lactase persistence. It is not known how the lactase gene is dramatically downregulated with age in most individuals but remains active in some individuals. We performed a comprehensive epigenetic study of human and mouse small intestines, by using chromosome-wide DNA-modification profiling and targeted bisulfite sequencing. Epigenetically controlled regulatory elements accounted for the differences in lactase mRNA levels among individuals, intestinal cell types and species. We confirmed the importance of these regulatory elements in modulating lactase mRNA levels by using CRISPR-Cas9-induced deletions. Genetic factors contribute to epigenetic changes occurring with age at the regulatory elements, because lactase-persistence and lactase-nonpersistence DNA haplotypes demonstrated markedly different epigenetic aging. Thus, genetic factors enable a gradual accumulation of epigenetic changes with age, thereby influencing phenotypic outcome.
In recent years, there have been considerable developments in techniques for the investigation and utilisation of enzymes. With the assistance of a co-author, this popular student textbook has been updated to include techniques such as membrane chromatography, aqueous phase partitioning, engineering recombinant proteins for purification and due to the rapid advances in bioinformatics/proteomics, a discussion of the analysis of complex protein mixtures by 2D-electrophoresis and RPHPLC prior to sequencing by mass spectroscopy. Written with the student firmly in mind, no previous knowledge of biochemistry, and little of chemistry, is assumed. It is intended to provide an introduction to enzymology, and a balanced account of all the various theoretical and applied aspects of the subject which are likely to be included in a course.
Many patients complain of abdominal symptoms with dairy products; however, clinical and psychosocial factors associated with self-reported lactose intolerance (SLI) have not been assessed in large studies. In particular, data are lacking from lactase deficient populations. This prospective cohort study assessed the prevalence of, and risk factors for, SLI in Chinese patients attending a gastroenterology clinic.
Consecutive patients completed questionnaires to assess digestive health (Rome III), psychological state (HADS), life event stress (LES), food intake, and quality-of-life (SF-8). A representative sample completed genetic studies and hydrogen breath testing (HBT) at the clinically relevant dose of 20 g lactose.
SLI was present in 411/910 (45%) clinic patients with functional abdominal symptoms. The genotype in all subjects was C/C-13910. A small number of novel SNPs in lactase promoter region were identified, including C/T-13908 which appeared to confer lactase persistence. Over half of the patients (54%) completed the 20 g lactose HBT with 58% (285/492) reporting typical symptoms. Positive and negative predictive values of SLI for abdominal symptoms during HBT were 60% and 44%, respectively. Psychological state and stress were not associated with SLI in clinic patients. SLI impacted on physical quality-of-life and was associated with reduced ingestion of dairy products, legumes, and dried fruit (p ≤ 0.05).
In a lactase deficient population, approximately half of patients attending clinic with functional gastrointestinal symptoms reported intolerance to dairy products; however, SLI did not predict findings on 20 g lactose HBT. Independent of psychosocial factors, SLI impacted on quality-of-life and impacted on food choices with restrictions not limited to dairy products.
© 2015 John Wiley & Sons Ltd.
Calcium is necessary for normal growth and bone development, as well as subsequent maintenance of bone density. The strongest argument for promotion of dairy ingestion is the beneficial effect of calcium (and fortified vitamin D in milk) on growth and development of the skeleton. Calcium is necessary for adequate bone accretion and optimal peak bone mass, which is a major determinant of risk for osteoporosis and fragility fractures later in adult life. Evidence suggests that certain age groups, such as children and teenagers, may be at increased risk for deficient bone acquisition if their diets are deficient in calcium or vitamin D. Weak evidence indicates that children with calcium-deficient diets have increased fracture rates. The maximal accumulation of bone mineral, and therefore the maximal calcium requirement, occurs during puberty. Although studies indicate that young children who drink milk are likely to meet or exceed the adequate intake for calcium, teenagers as a group tend not to take in enough calcium to meet recommended needs. This problem is exacerbated by dairy avoidance in individuals who consider themselves lactose intolerant, regardless of whether they have undergone objective testing for lactose intolerance.
Objetivo Evaluar el impacto económico y la relación coste-efectividad de la introducción de LacTEST, un nuevo test de diagnóstico que determina el grado de hipolactasia en adultos con síntomas clínicos de hipolactasia, en el mercado español. Metodología Se desarrolló un modelo de impacto presupuestario utilizando la perspectiva del Sistema Nacional de Salud (SNS) español con un horizonte temporal de 4 años. Se estimó el impacto económico basándose en el número de test de diagnóstico para hipolactasia indicados en diferentes hospitales en España, la utilización de recursos sanitarios, los costes unitarios y las cuotas de mercado. Los test de diagnóstico comparados fueron el test de hidrógeno espirado combinado con el test de glucemia capilar, la biopsia intestinal, el test de acidez de las heces, el test genético y LacTEST. Los costes considerados fueron los de los test de diagnóstico, las pruebas analíticas y el tiempo del personal sanitario. Todos los costes se expresaron en euros del año 2012, y se aplicó una tasa de descuento del 3% anual. Los costes directos anuales por paciente con cada test de diagnóstico se calcularon antes y después de la introducción de LacTEST, con el fin de estimar los costes totales anuales. Para el análisis de coste-efectividad se utilizó un árbol de decisiones para comparar el test de hidrógeno espirado, el test de glucemia capilar, la biopsia intestinal y LacTEST. Resultados La población objetivo se estimó como constante en 329.219 para los próximos 4 años. Los costes totales se estimaron en 394,2 millones de € sin la introducción de LacTEST y en 366,2 millones de € después de su introducción. En cuanto a coste-efectividad LacTEST resultó más efectivo en el caso base, con una sensibilidad y especificidad más altas, frente al test de hidrógeno y glucemia capilar. Además LacTEST fue menos costoso que el test de hidrógeno y la biopsia intestinal. Conclusiones La introducción de LacTEST mostró una reducción en el impacto presupuestario para el SNS español. El ahorro en la carga económica de los test de diagnóstico de hipolactasia se estimó en unos 28 millones de € para los próximos 4 años. Además LacTEST fue una opción coste-efectiva en comparación con los otros test de diagnóstico.
Although the prevalence of lactose malabsorption is high and the importance of this diagnosis is established in gastroenterological practice, still a variety of poorly standardized tests is used to investigate the ability of the small bowel to digest lactose. In this report the various most commonly used lactose malabsorption tests are described and compared with each other knowing that a ‘gold standard’ does not exist. The hydrogen breath test is the test most used in clinical practice. On the basis of recent investigations the recommendation is made to improve the accuracy of this test by prolonging it to 4 hours and by simultaneous measuring of the oro-coecal transit time.
Dried carriers based on agarose and starch as filler entrapping the enzyme lactase were studied. After freeze-drying, all carriers had a spherical shape, resembling the properties of porous cellular solids. The inclusion of starch resulted in a rough surface of the dried carriers. The dried carriers were coated with chocolate to facilitate enzyme protection and their possible inclusion within functional food products. Lactase release from non-coated and chocolate-coated carriers revealed that the conditions in buffer and stomach-simulating solution led to a first mode of release due to lactase molecules located on the external or inner surfaces of the carrier but not within the matrix itself. In addition, chocolate coating led to a second mode of lactase release greater than the initial release. Thus, chocolate coated agarose-lactase-containing carriers may be considered for utilization in functional foods for lactose intolerant people.
OBJECTIVES: Bloating and distention are often attributed to dietary factors by patients with irritable bowel syndrome (IBS). This study examined the effects of gas production and visceral hypersensitivity on digestive symptoms after lactose ingestion in a population with lactase deficiency.
METHODS: IBS patients (n=277) and healthy controls (HCs, n=64) underwent a 20-g lactose hydrogen breath test (LHBT) with evaluation of hydrogen gas production and lactose intolerance (LI) symptoms. Abdominal distention (199 IBS, 40 HCs) was measured during LHBT. Rectal sensitivity (74 IBS, 64 HCs) was assessed by barostat studies.
RESULTS: Hydrogen production and distention were similar in IBS patients and HCs during LHBT; however, LI was more frequent in IBS (53.8 vs. 28.1%, P<0.001), especially bloating (39.0% vs. 14.1%, P<0.001) and borborygmi (39.0 vs. 21.9%, P=0.010). Only 59.0% of patients with bloating had distention. No correlation was observed between girth increment and bloating (P=0.585). IBS patients had lower rectal sensory thresholds (P=0.001). Multivariate analysis indicated that hydrogen production increased bloating (odds ratio (OR) 2.19, 95% confidence interval (CI) 1.09-4.39, P=0.028) and borborygmi (OR 12.37, 95% CI 3.34-45.83, P<0.001) but not distention (P=0.673). Visceral hypersensitivity was associated with bloating (OR 6.61, 95% CI 1.75-25.00, P=0.005) and total symptom score (OR 3.78, 95% CI 1.30-10.99, P=0.014).
CONCLUSIONS: Gas production and visceral hypersensitivity both contribute to digestive symptoms, especially bloating and borborygmi, in IBS patients after lactose ingestion. Objective abdominal distention is not correlated with subjective bloating.
Background & aims
Lactose malabsorption (LM) is a frequent condition in adults and is often associated with bowel symptoms. Although the diagnostic gold standard is represented by assessment of the tissue lactase activity, LM diagnosis is currently made non-invasively by hydrogen breath test. Alternatively, an accurate clinical and anamnestic evaluation of symptoms can suggest LM in many cases. The aim of the study was to evaluate the diagnostic accuracy of clinical variables for the diagnosis of LM when compared to the hydrogen breath test.
Methods
Forty consecutive patients with suspected LM performed a hydrogen breath test after oral load of lactose (25 g). Patients were requested to answer five questions on a visual-analogical scale (0–4): subjective correlation milk/symptoms; abdominal pain; bloating; soft stools; response after milk exclusion. Statistical analysis was performed by using the Mann–Whitney U-test and Cohen's k of agreement. Also, a ROC curve was constructed to identify the best diagnostic cut-off for the resulting clinical-anamnestic score.
Results
Breath test was positive in 16 out of 40 patients (40%). The mean clinical score was significantly higher in patients with LM (14 vs 8.5; p < 0.001). On ROC curve a clinical score >10 showed a sensitivity of 91%, a specificity of 95%, positive and negative predictive values of 91% and of 95% for LM diagnosis. Additionally, a score >10 presented high concordance with the result of the breath test (k = 0.92).
Conclusions
Accurate evaluation of five clinical-anamnestic variables, with the use of a simple scoring system, is almost equivalent to the hydrogen breath test for the diagnosis of lactose malabsorption and could avoid breath testing in many cases.
BACKGROUND & AIMS: The effects of lactase deficiency on digestive symptoms and diet in patients with irritable bowel syndrome (IBS) have not been well defined. We assessed lactose absorption and tolerance and the intake of dairy products in healthy volunteers (controls) and patients with diarrhea-predominant IBS (D-IBS).
METHODS: Sixty patients diagnosed with D-IBS at the Sir Run Run Shaw Hospital, Hangzhou, China and 60 controls were given hydrogen breath tests to detect malabsorption and intolerance after administration of 10, 20, and 40 g lactose in random order 7-14 days apart; participants and researchers were blinded to the dose. We assessed associations between the results and self-reported lactose intolerance (LI).
RESULTS: Malabsorption of 40 g lactose was observed in 93% of controls and 92% of patients with D-IBS. Fewer controls than patients with D-IBS were intolerant to 10 g lactose (3% vs 18%; odds ratio [OR], 6.51; 95% confidence interval [CI], 1.38-30.8; P = .008), 20 g lactose (22% vs 47%; OR, 3.16; 95% CI, 1.43-7.02; P = .004), and 40 g lactose (68% vs 85%; OR, 2.63; 95% CI, 1.08-6.42; P = .03). H(2) excretion was associated with symptom score (P = .001). Patients with D-IBS self-reported LI more frequently than controls (63% vs 22%; OR, 6.25; 95% CI, 2.78-14.0; P < .001) and ate fewer dairy products (P = .040). However, self-reported LI did not correlate with results from hydrogen breath tests.
CONCLUSIONS: The risk of LI is related to the dose of lactose ingested and intestinal gas production and is increased in patients with D-IBS. Self-reported LI, but not objective results from hydrogen breath tests, was associated with avoidance of dairy products. ClinicalTrials.gov, Number: NCT01286597.
Traducción de: Human nutrition in the developing world Incluye bibliografía
Las reacciones adversas a los alimentos son episodios frecuentes en la población general. Sin embargo, el conocimiento exacto de los alérgenos alimentarios y los mecanismos implicados en estos procesos es pobre. En 1995 el Subcomité de Reacciones Adversas de la Academia Europea de Alergología e Inmunología Clínica propuso una clasificación de las reacciones adversas a los alimentos, basada más en los mecanismos fisiopatológicos que en las manifestaciones clínicas. De acuerdo con esta clasificación, las reacciones no tóxicas se pueden dividir en alergia alimentaria, cuando intervienen mecanismos inmunológicos, e intolerancia alimentaria, cuando no media un mecanismo inmunológico. El tratamiento principal de la intolerancia alimentaria consiste en la eliminación del alimento en cuestión de la dieta habitual. Por otro lado, hay tratamientos específicos para algunos tipos de intolerancias alimentarias (por ejemplo, betagalactosidasas en los casos de hipoabsorción de lactosa).
The relation between gastric emptying and the intragastric distribution of 300 ml radiolabelled beef consommé with and without 60 g margarine was investigated by performing randomised, paired gammacamera studies in seven healthy male volunteers (aged 20-22 years). The low calorie bland meal emptied rapidly from both the proximal and distal stomach after a short lag period (4-6 min), during which 24-50% of the liquid passed into the distal stomach. Addition of margarine to the liquid test meal increased the lag period (median 32 min, range 7-60 min; p less than 0.01) and decreased the slope of emptying (T1/2 lag period 88 min, 49-146 min v 15 min, 10-57 min; p less than 0.01). During the lag period there was an initial filling of the distal stomach, similar to that with the bland liquid, followed by a redistribution of between 19% and 61% (median 46%) of the distal stomach contents back into the proximal stomach. At the onset of emptying, the distal stomach filled (median 30%, range 16-34%) and during this time the proximal stomach emptied twice as fast as the whole stomach (p less than 0.05). Thereafter, the distal stomach capacity remained relatively constant while both the proximal and whole stomach emptied at similar rates. This study shows that the delay in gastric emptying of a liquid that has a high fat content is due in part to a redistribution of distal stomach contents back into the proximal stomach.